It's pretty common knowledge that virus scanners and games do not mix. That's not saying that they NEVER mix, but generally, they do not work well together.
The problem is that a lot of Virus scanners do active protection. They are constantly scanning files, which can cause a couple of problems. First it slows the machine down..it adds an extra layer of complexity. Secondly, it can lock up files that the game is requetsing.
For example, there was a recent issue with EQ and AVG Anti-Virus that was causing a 1 - 2 second lag opening any new windows. This made casting spells, or opening the inventory screen very difficult.
Best option is to just disable anti-virus while playing. You can always do a virus scan after you are done to make sure that your PC is still not infected.
Edited, Fri Jul 15 08:26:02 2005 by Frakkor